This invention relates generally to mechanical mounting structure and more particularly to precision electromechanical sensory mounting structure having a requirement for precision alignment and typically used in a varying thermal environment.
In precision instrumentation, such as multisensor accelerometers and gyros, a number of diverse engineering requirements such as alignment accuracy, thermal stress tolerance, and cost-effectiveness, must all be considered in the design.
In one such device, a multiple sensor head is mounted on a centrally disposed support shaft and the shaft must be firmly attached to the sensor housing. Various methods of supporting the sensor shaft have been utilized such as clamps, pins, and setscrew retainers. Each of these methods has the capability of holding a shaft firmly; however, none of the previously-mentioned clamping means tolerates temperature induced variations in the dimensions of the shaft itself.
As the shaft temperature increases, there is a known amount of physical expansion which, across the diameter of the shaft, tends to be acceptable in most applications. However, the dimensional change along the central or longitudinal axis of the shaft tends to be much greater, and when utilizing rigid clamping means at both ends of such a shaft, tends to distort the output of the sensor head, thus generating erroneous or faulty data.
Additionally, a requirement for rigid lateral affixation of both ends of the shaft requires particular attention to tolerances in the manufacture of the components of such a device as well as prevention of any lateral free-play in the mounting structures.